Request for an AD/ADRD-focused administrative supplement to the K01 ?Pathways from Health Insurance to Subjective Well-Being and Psychological Health at Older Ages? (K01AG050811) to collect and analyze data on (dementia-related) cognitive functioning, mental health and subjective well-being among older Americans Abstract The American population over 65 is growing rapidly, which will lead to a steep rise in the number of dementia cases. Cognitive impairment is often associated with limitations in an individual's ability to work, manage finances, and deal with routine activities, with implications for the psychological well-being of seniors. As a result, there is an urgent need to identify opportunities for delaying cognitive decline and dementia onset, and to mitigate the welfare consequences of cognitive impairment. In this administrative supplement, we will investigate the possible role that health insurance (in particular Medicare) might have in delaying cognitive decline. Recent work suggests that gaining health insurance coverage improves subjective well-being (SWB) and reduces mental illness (see, for example, Baicker et al. 2013 and Finkelstein et al. 2012). However, our current understanding of whether these results hold in more general contexts and the channels through which they operate is quite limited. In my K award, I have been studying how Medicare affects SWB and mental health to shed light on these issues. The results I have produced during the two first years of the parent grant suggest that Medicare improves psychological well-being and that stressors (such as financial strain and exposure to catastrophic medical expenditure risk) are an important mechanism through which these effects take place. I request an administrative supplement to investigate the effects of Medicare on the cognitive functioning, mental health and subjective well-being (SWB) of seniors. Through the collection and analysis of primary data in addition to secondary data analysis, the supplement would allow me to extend the initially proposed analyses in my K award to include the study of cognition and Alzheimer's disease. All other parts of the initially proposed work, including the methods, will remain unchanged. The measures of cognitive functioning to be collected and analyzed have been shown to predict cognitive decline and/or dementia. This is a promising area of research for early investigators like myself. Finally, the primary data collected will be used to shed light on the mechanisms behind the effects of Medicare on cognitive functioning and SWB. Understanding the impact of health insurance on cognitive decline and psychological well-being is important for numerous reasons. First, cognitive impairment has very high direct and indirect costs and its prevalence is increasing rapidly with population aging. Second, investigating how Medicare affects cognition and well-being will help document what might be a large and potentially overlooked benefit of health insurance. Finally, understanding the mechanisms behind this relationship can offer new and important insights into ways to delay cognitive decline and improve the mental health and SWB of seniors.